The present proposal is undertaken to characterize the alterations in myocardial metabolism during endotoxic shock, and to delineate the mechanisms responsible for these alterations. Finally, attempts will be made to prevent the onset or delay the progression of cellular derangements during shock. The proposed experiments involve uptake and oxidation of substrates by the myocardium, translocation of adenine nucleotides across mitochondrial membrane, and sodium-potassium membrane pump activity. The information to be obtained from these studies will be useful in the understanding of the pathophysiology of heart during endotoxic shock.